Jabir (b. Abdullab) (RA) reported Allah's Messenger (ﷺ) as saying: Odd number of stones are to be used for cleaning (the private parts after answering the call of nature), and casting of pebbles at the Jamras is to be done by odd numbers (seven), and (the number) of circuits between al-Safa' and al-Marwah is also odd (seven), and the number of circuits (around the Ka’bah) is also odd (seven). Whenever any one of you is required to use stones (for cleaning the private parts) he should use odd number of stones (three, five or seven).
Explanation & Benefits
Shaykh Maulana Abdul Aziz Alvi
Hadith Footnote:
Vocabulary of the Hadith:
Taw:
Its meaning is "odd" (an odd number).
Benefits and Issues:
Seven pebbles must be thrown at each Jamrah, and with each pebble, "Allahu Akbar" should be said, except at Jamrah Aqabah. At every Jamrah, one should stand facing the Qiblah, raise the hands, and make supplication (du'a). If fewer than seven pebbles are thrown, then the details regarding this have already been mentioned in the benefit of Hadith number 271.
Source: Tuhfat al-Muslim: Commentary on Sahih Muslim, Page: 3143